CVE-2026-52881: MantisBT Cross-Site Scripting Vulnerability

CRITICAL
Advisory Identifier: GHSA-vcrw-4xvv-jh49
Share
CWE-79
Published
Advisory Summary

CVE-2026-52881 is a CRITICAL cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting MantisBT libraries in the Packagist ecosystem. The issue involves reflected xss in admin/install.php via unescaped printf. Remediation is available by upgrading affected packages to version 2.28.4.

CVE-2026-52881 at a Glance

CVE Identifier CVE-2026-52881
GHSA Identifier GHSA-vcrw-4xvv-jh49
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product MantisBT
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-52881

To remediate this vulnerability, upgrade all affected MantisBT dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mantisbt/mantisbt fixed: 2.28.4 
Upgrade mantisbt/mantisbt to 2.28.4
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for mantisbt/mantisbt

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-52881, inspect your project dependencies for MantisBT:

inspect dependencies for mantisbt/mantisbt

Analyze the terminal output to locate any version of MantisBT in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.28.4), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In MantisBT, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

MantisBT 2.28.3 and earlier contains six reflected XSS injection points in `/admin/install.php`. User-supplied parameters are echoed into HTML without escaping via an unescaped printf format string. No authentication is required. A Content Security Policy (script-src 'self') prevents inline JavaScript execution, but the CSP is missing a form-action directive, allowing exploitation via credential-phishing form injection and <meta> open redirects. ### Impact - Credential phishing: Attacker crafts a URL that renders a fake login form on the real MantisBT admin page. Admin credentials are submitted to an attacker-controlled server. - Open redirect: Victim is silently redirected to a phishing or malware site. - UI manipulation: CSS injection can hide legitimate page content and overlay attacker-controlled HTML, enabling social engineering. ### Patches - https://github.com/mantisbt/mantisbt/commit/297773fbb238c39a153bd888431b41a176132098 ### Workarounds Remove the `/admin` directory, as [recommended in the Admin Guide](https://mantisbt.org/docs/master/en-US/Admin_Guide/html-desktop/#admin.install.postcommon) ### Resources - https://mantisbt.org/bugs/view.php?id=37103 - related advisory [GHSA-77x8-3v3h-hrhv](https://github.com/mantisbt/mantisbt/security/advisories/GHSA-77x8-3v3h-hrhv) ### Credits McCaulay Hudson (@_McCaulay) of watchTowr

CVE-2026-52881 Affected MantisBT Versions

1 component(s)
Fixed Versions:
2.28.4
Product / Package Ecosystem Affected Versions Fixed Version
mantisbt/mantisbt
 Packagist
< 2.28.4
2.28.4

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mantisbt/mantisbt/security/advisories/GHSA-vcrw-4xvv-jh49
Security Fix Commit FIX COMMIT
https://github.com/mantisbt/mantisbt/commit/297773fbb238c39a153bd888431b41a176132098
MantisBT Source Repository REPOSITORY
https://github.com/mantisbt/mantisbt
MantisBT Security Information SECURITY
https://mantisbt.org/bugs/view.php?id=37103

Frequently Asked Questions

What is CVE-2026-52881?
CVE-2026-52881 is a security vulnerability in MantisBT involving Reflected XSS in admin/install.php via unescaped printf under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which MantisBT versions are affected?
Affected versions include releases prior to 2.28.4 across affected packages: mantisbt/mantisbt.
What version fixes CVE-2026-52881?
Upgrading to 2.28.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mantisbt/mantisbt affected?
Yes, mantisbt/mantisbt is affected in releases prior to 2.28.4. Upgrade your dependency to 2.28.4 or later.
What CWE is associated with CVE-2026-52881?
CVE-2026-52881 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-52881?
Run the dependency tree command: 'inspect dependencies for mantisbt/mantisbt'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vcrw-4xvv-jh49",
  "modified" : "2026-07-15T18:34:36Z",
  "published" : "2026-07-15T18:34:36Z",
  "aliases" : [ "CVE-2026-52881" ],
  "summary" : "MantisBT: Reflected XSS in admin/install.php via unescaped printf ",
  "details" : "MantisBT 2.28.3 and earlier contains six reflected XSS injection points in `/admin/install.php`. User-supplied parameters are echoed into HTML without escaping via an unescaped printf format string. No authentication is required.\n\nA Content Security Policy (script-src 'self') prevents inline JavaScript execution, but the CSP is missing a form-action directive, allowing exploitation via credential-phishing form injection and <meta> open redirects.\n\n### Impact\n- Credential phishing: Attacker crafts a URL that renders a fake login form on the real MantisBT admin page. Admin credentials are submitted to an attacker-controlled server.\n- Open redirect: Victim is silently redirected to a phishing or malware site.\n- UI manipulation: CSS injection can hide legitimate page content and overlay attacker-controlled HTML, enabling social engineering.\n\n### Patches\n- https://github.com/mantisbt/mantisbt/commit/297773fbb238c39a153bd888431b41a176132098\n\n### Workarounds\nRemove the `/admin` directory, as [recommended in the Admin Guide](https://mantisbt.org/docs/master/en-US/Admin_Guide/html-desktop/#admin.install.postcommon)\n\n### Resources\n- https://mantisbt.org/bugs/view.php?id=37103\n- related advisory [GHSA-77x8-3v3h-hrhv](https://github.com/mantisbt/mantisbt/security/advisories/GHSA-77x8-3v3h-hrhv)\n\n### Credits\nMcCaulay Hudson (@_McCaulay) of watchTowr",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mantisbt/mantisbt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.28.4"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.28.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/security/advisories/GHSA-vcrw-4xvv-jh49"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/commit/297773fbb238c39a153bd888431b41a176132098"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mantisbt/mantisbt"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=37103"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-15T18:34:36Z",
    "nvd_published_at" : null
  }
}